Ionising vs non-ionising
X-rays and gamma rays have enough energy per photon to knock electrons off atoms — that is how they damage DNA. Microwaves don't. A 2.45 GHz photon carries about 1 millionth of the energy needed to ionise. The only way microwaves harm tissue is by heating it.
The thermal limit
IEEE C95.1 and ICNIRP both set safety limits to keep tissue heating below 1°C in any 6-minute period. For the general public this is 10 W/m² at 10 GHz. A radar antenna at full power can briefly exceed this in its main beam — that's why fences exist around high-power air-defence radars.
Realistic exposure
A Wi-Fi router puts about 0.1 W out and you sit metres away — exposure is around 0.001 W/m², 10,000 times below the limit. A police speed gun is around 0.1 W in a narrow beam; officers are trained not to point it at themselves. An airport surveillance radar is 1 MW peak, but its duty cycle is 0.1%, so average power is 1 kW spread over a huge sphere.
Where to worry
Close-in maintenance on transmitting military radars without the safety interlocks. Standing in front of an active satellite uplink. Microwave oven door seals damaged enough to leak. None of these match the 'kitchen microwave is irradiating your house' stories online.